The parallel demands for more dense and cost-effective electronic memories, and for ever faster computer processors, have inspired enormous scientific and technological advances over the past 50 years. Expensive, unreliable, and voluminous vacuum-tube-based computational systems were replaced by transistor-based computational systems, in turn replaced by integrated-circuit-based computational systems of ever decreasing feature dimensions and ever increasing densities and switching speeds. As certain fundamental physical limits to further decreasing the feature dimensions of integrated circuits produced by photolithographic methods have begun to be approached, significant research and development efforts have been applied to newer, molecular-electronics-based logic circuits and, ultimately, molecular-electronics-based processors, memories, and integrated computational systems.
Molecular electronics provide a significant leap with respect to feature dimensions and electronic component densities, but also present new and challenging problems. Recently, for example, nanowire-crossbar memories have been developed for storing information in nanowire junction at the nanowire intersections of a grid-like nanowire crossbar. Techniques have been developed for addressing a particular nanowire junction and for changing the state of the nanowire junction repeatedly between two different and electronically detectable conductivity states. However, nanowire-crossbar-memory designers and manufacturers have recognized the need for a method and device to allow for accessing an individual nanowire junction within a nanowire-crossbar memory in order to determine which of two conductivity states the nanowire junction currently inhabits. In other words, while the nanowire-crossbar memories, and methods for writing information to the nanowire-crossbar memories, have been developed, manufacturers and designers of nanowire-crossbar memories continue to seek a method and implementation for reading the contents of nanowire-crossbar memories that can be economically, reliably, and feasibly manufactured.